Annotation of wikisrc/kyua/import.mdwn, revision 1.2

1.1 jmmv 1: [[!meta title="Kyua: The way into NetBSD"]]
2: [[!toc levels=2]]
3:
4: **Project owner: [Julio Merino](mailto:jmmv@NetBSD.org).**
5: **Status: draft as of 2012-08-31; not even sent for review yet.**
6:
7: The import of Kyua into NetBSD to replace the deprecated ATF tools is
8: planned to happen in NetBSD 7.0. The ATF libraries will remain in place,
9: and as such no changes will happen to the tests that already live in
10: `src/tests`.
11:
12: The transition from ATF to Kyua includes steps and tools to offer backwards
13: compatibility with users that may rely on the ATF tools shipped since
14: NetBSD 5.0. These backwards compatibility tools cover the most common use
15: cases but might not be perfect initially. Despite these provisions, this
16: plan should be executed well in advance the creation of the 7.0 branch to
17: ensure there is enough time in NetBSD-current to flesh out any major
18: problems.
19:
20: Before moving on, please read the
1.2 ! jmmv 21: [[Kyua: An introduction for NetBSD users|/kyua]] page. You should be
1.1 jmmv 22: familiar with the structure of Kyua and its major components to be able to
23: review this plan.
24:
25: # Proposed changes
26:
27: The final user visible changes that this project will bring to NetBSD are
28: as follows. Because these change the availability of tools that have
29: already been shipped since 5.0, the modifications are staged to happen
30: across two major releases:
31:
32: ## For NetBSD 7.0
33:
34: * Addition of the new `kyua` command-line tool. This provides the runtime
35: engine for the test programs (`atf-run`'s functionality) and the ability
36: to generate reports of the results in plain text form and HTML form
37: (`atf-report`'s functionality). This tool is able to execute all the
38: existing test programs without modifications.
39:
40: * Replacement of the `Atffile`s files in `/usr/tests` with `Kyuafile`s.
41:
42: * Ability to generate HTML reports right form the base system, with such
43: reports hooked into the various continuous build systems.
44:
45: * Replacement of the `atf-run` and `atf-report` tools with shell scripts
46: that provide backwards compatibility implementations based on `kyua`.
47: These can deal with old-style `Atffile`s so that users with custom test
48: suites can continue to run them.
49:
50: * Introduction of a new `atf2kyua` script to convert old `Atffile`s to
51: `Kyuafile`s. This is used internally by the compatibility `atf-run`
52: script, but can also be invoked by the end user by hand to deal with his
53: own test suites. Could be placed into `libexec` if we do not want to
54: make this public.
55:
56: ## For NetBSD 8.0
57:
58: * Removal of the backwards compatibility `atf-run` and `atf-report`
59: scripts, as well as the supporting `atf2kyua` tool.
60:
61: # Why now?
62:
63: Kyua has existed for almost 3 years already, so you may be wondering why
64: this import is being proposed now. The major reasons are:
65:
66: * Since 0.5, Kyua has now feature-parity with ATF. Replacing the ATF tools
67: with Kyua should not introduce functionality regressions.
68:
69: * NetBSD-6 has been branched relatively recently, so we can expect NetBSD-7
70: to be far away enough in the future to provide plenty of time to
71: stabilize Kyua in NetBSD-current.
72:
73: * The existence of the deprecated `atf-run` and `atf-report` tools hinders
74: the development of new features that require changes to the inteface of
75: ATF test programs. As an example: a highly requested feature is the
76: ability to change the timeout settings of the test programs (for the
77: benefit of old, slow platforms); doing this in the ATF codebase is
78: tricky.
79:
80: * Some developers continue to add old-style tests to the tree. While this
81: is suboptimal and against the policy dictated by core@, Kyua brings in a
82: mechanism to allow running these tests unmodified (i.e. without adding
83: any ATF calls in their code). This, in turn, will let such developers
84: add their tests more easily, and thus increase the tests coverage.
85:
86: # The plan
87:
88: This section details what the transition plan looks like and an estimate
89: timeline. As all things that depend on free time (opensource software
90: hacking, in this case), take the estimates with a grain of salt.
91:
92: ## Discuss this plan in tech-userlevel@
93:
94: If you are here it's possibly because a review request for this plan has
95: already been published and thus the plan has already begun. If
96: not... well, hold off for a little bit ;-)
97:
98: This plan will be sent to the tech-userlevel@ mailing list asking for
99: comments. **Two weeks shall be allowed for initial discussion.** Depending
100: on the outcome, the plan and/or the software will need to be adjusted
101: (which in turn may require significant amounts of time not yet accounted
102: for). I'll be optimistic for now.
103:
104: ## Get core@ approval
105:
106: By policy, the import of any new software component into src requires core@
107: approval. Even though this will have been discussed at length in
108: tech-userlevel@ (as per the previous step), the final decider on this issue
109: will be core@. The corollary of this is that, if no consensus can be
110: reached in tech-userlevel@ regarding this plan, core@ will be asked to come
111: up with a decision.
112:
113: If core@ approves the plan, the next steps shall start immediately. If
114: core@ disagrees, core@ will be asked to provide advice on the corrections
115: that should be made before the plan can be approved.
116:
117: ## Import Kyua into src
118:
1.2 ! jmmv 119: As the [[introductory page to Kyua|/kyua]] describes, Kyua has been
! 120: available in pkgsrc for a while and can be readily installed and used to
! 121: run the tests from `/usr/tests`.
1.1 jmmv 122:
123: However, because ATF lives in src, and because NetBSD aims to provide the
124: best environment for testing "out of the box", Kyua should be imported into
125: src just like ATF was. The major reasons for this, as have been explained
126: in the past, are: first, to allow any new deployment of NetBSD to be
127: validated right after installation and continuously afterwards; and,
128: second, to permit the execution of tests during development without having
129: to install any additional software.
130:
131: The specific steps to perform this import are:
132:
133: 1. Import Lutok into `external/bsd/lutok/`. This is a shared library that
134: wraps the native Lua C interface in C++. Lutok was originally part of
135: Kyua, and was split into its own package per the request of some users
136: that found this component useful on its own.
137:
138: 1. Import Kyua into `external/bsd/kyua-cli/`. This yields a new kyua
139: binary in `/usr/bin`, a lot of test programs in `/usr/tests/kyua-cli`
140: (around 100) and some auxiliary files in `/usr/share/kyua`.
141:
142: 1. Protect all products of Lutok and Kyua with the existing `MKATF` knob.
143: If desired, these could instead be protected by a new and separate
144: `MKKYUA` knob, but because the transition is only temporary, I do not
145: think it's worth the effort.
146:
147: 1. Update `bsd.test.mk` to generate `Kyuafile`s *in addition to*
148: `Atffile`s.
149:
150: There is no real need to do this import in a branch given that this import
151: only adds new functionality without touching existing stuff.
152:
153: All the preparatory work for the import can be done offline (in about two
154: weeks at most, given that I have mot of this ready). Aside from the code
155: changes, this will involve the validation of NetBSD/amd64, NetBSD/i386 and
156: NetBSD/macppc builds (which are the ports I have access to). If you
157: consider that some other tricky architecture should be build-tested
158: (sparc64?), let me know and I'll include it in the list.
159:
160: The submission step to CVS, once all the code changes are ready locally,
161: and any post-commit validation checks will take a few hours. Any build
162: breakage should be addressed in a timely manner (and can possibly be
163: worked-around by setting `MKATF=no`).
164:
165: ## Update documentation
166:
1.2 ! jmmv 167: The [[Kyua: An introduction for NetBSD users|/kyua]] wiki page will be
1.1 jmmv 168: updated to explain how Kyua is bundled in NetBSD and how to use the bundled
169: version.
170:
1.2 ! jmmv 171: The [[Creating atf-based tests for NetBSD src|/tutorials/atf]] wiki page
! 172: will be updated to account for the differences in test programs execution
! 173: with Kyua instead of ATF.
1.1 jmmv 174:
175: The afterboot(8) and tests(7) manpages will be adjusted to mention `kyua`
176: instead of the ATF tools.
177:
178: ## Adjust continuous testing systems to use Kyua
179:
180: With `kyua` being part of the release sets, it is possible to adjust the
181: continuous test systems to make use of this tool in the test environments
182: without having to take any additional step.
183:
184: I'll work with gson@ and pgoyette@ to adapt their continuous testing
185: machines to use the new built-in `kyua` binary instead of `atf-run` and
186: `atf-report`. I'm planning to do the necessary work to change `anita`
187: myself, and I expect to help them deploy the changes to their own systems.
188: Because Kyua and ATF will cohexist in the base system at this point,
189: migrating the continuous testing systems to Kyua can happen at its own
190: peace.
191:
192: It might happen that Kyua misses some little detail needed by these
193: systems. In that case, this may require a new release of Kyua and a
194: reimport into the tree. Incremental imports with new features are much
195: easier than the original import described in here. Also, it will be
196: possible to cherry-pick any external changes into the tree without a
197: reimport (as has often been done in ATF).
198:
199: ## User validation period
200:
201: At this stage, **at least one month shall be given to the community** to
202: test the new tools and the new test results dashboards. Collect feedback
203: and address requests as appropriate.
204:
205: ## Replace atf-run and atf-report with kyua-atf-compat
206:
207: Import the Kyua-based `atf-run` and `atf-report` compatibility tools and
208: stop building the deprecated versions of these. The compatibility versions
209: are shipped in a separate `kyua-atf-compat` package, and thus this will be
210: imported into `external/bsd/kyua-atf-compat/`.
211:
212: Once this is done, change `bsd.test.mk` to not generate `Atffile`s any
213: more, as the compatibility tools do not need them.
214:
215: ## Drop atf-run and atf-report's code
216:
217: Delete the native `atf-run` and `atf-report` utilities from the source tree
218: (and from the upstream repository). This also gets rid of a lot of
219: supporting helper code, which makes the various ATF libraries leaner (and
220: therefore benefits all test programs!).
221:
222: ## Get rid of some ATF wrappers as a proof of concept
223:
224: There are some test programs (e.g. the ones in the ipf test suite) that are
225: not ATF-based. To plug them into the NetBSD test suite, we have
226: implemented ATF-based wrappers that invoke the original plain tests. This
227: is certainly suboptimal, as this level of indirection hinders readability
228: and makes development harder. (In particular, it prevents some key
229: developers from contributing tests in the first place.)
230:
231: Because Kyua has the ability to run these "plain" (non-ATF) test programs
232: directly, and because a bunch of developers are really looking forward to
233: this feature, I will convert a few tests to not include ATF wrappers as a
234: proof of concept of this feature. The ipf tests are probably a good choice
235: for this.
236:
237: ## Remove atf-run and atf-report compatibility tools
238:
239: This is still really far away in the future (needs to happen after NetBSD
240: 7.0 is branched), but I'm listing it for completeness of the plan. The
241: idea is to get rid of any ATF compatibility scripts by NetBSD 8.0. This
242: gives end users a full release cycle (that of 7) to adapt to Kyua while at
243: the same time being able to use the old-style tools.
244:
245: # Possible concerns
246:
247: This section attempts to collect the list of possible concerns and/or
248: objections that may come up during the review, together with an attempt of
249: rebuttal from my side.
250:
251: ## Increased compilation time
252:
253: The addition of any new component to src increases the build time of the
254: whole system. In the case of Kyua, this increase might be noticeable
255: *because of the large amount of test programs provided (roughly 100)*, all
256: of which are in C++.
257:
258: Note that ATF also had a relatively large codebase and a bunch of tests
259: (although not as many). The "trick" was that the majority of these tests
260: were written in shell, and as such they did not increase the build time by
261: much. However, they significantly increased the run time of the test
262: suite, and they were less detailed (mostly integration tests, few unit
263: tests) than the Kyua tests.
264:
265: In order to mitigate this issue, the build of all pieces of Kyua will be
266: protected by `MKATF` so that people allergic to C++ can avoid the whole
267: thing. Even more, there are some other additional provisions described
268: below.
269:
270: ## Introduction of more C++ code in base
271:
272: First of all, why did I use C++? To make the implementation simpler and
273: safer (the RAII programming pattern is really useful in avoiding memory and
274: resource leaks with minimal effort). And C++ is part of the base system
275: and a supported language, so there was no reason not to do so. But that's
276: not the point of this item: if you don't like C++, this is not going to
277: convince you otherwise.
278:
279: It's true that, if we count the number of lines, Kyua brings in more C++
280: code than what will eventually be dropped by the removal of the ATF tools.
281: However, because ATF was also C++, the import of Kyua itself does not make
282: the situation significantly worse.
283:
284: Additionally, the two compilers we can really use (GCC and LLVM) already
285: use, or will soon use, C++ in their code base. It is unlikely that we will
286: be able to remove all C++ support from base anytime soon due to this, while
287: at the same time keeping support for all the ports that NetBSD has.
288:
289: Long term, if the use of C++ proves to be a problem, there are a few things
290: that can be done to slowly get rid of it that have been floating my mind
291: recently. The first is the rewrite of the performance-critical parts of
292: Kyua in plain C. This would involve splitting the runtime engine of a
293: single test case in its own binary (which, for other reasons may be a good
294: idea on its own). The second is the rewrite of most user-interface code in
295: Lua, which in itself would bring some extensibility advantages to the
296: program. Both options will be investigated when the time permits. In the
297: meantime, the replacement of ATF with Kyua does not make things worse; it
298: just changes one chunk of code with another.
299:
300: ## No need for Lutok as a public library
301:
302: Kyua depends on Lutok, which is a C++ interface to Lua. The code of this
303: library was originally part of Kyua, but I split it into its own project
304: because some users asked for it.
305:
306: If there is no desire to ship Lutok as a shared library in `/usr/lib`, we
307: can build Lutok as a static private library and link Kyua against it.
308: There is no need to install this as a shared library.